package com.base.core.util;

import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;


public class StringArray {  
    public static void main(String[] args) {  
        //测试union  
        String[] arr1 = {"abcd", "dfa", "abcd"};  
        String[] arr2 = {"abc", "cc", "df", "d", "abc"};  
        String[] result_union = union(arr1, arr2);  
        System.out.println("求并集的结果如下：");  
        for (String str : result_union) {  
            System.out.println(str);  
        }  
        System.out.println("---------------------可爱的分割线------------------------");  
  
        //测试insect  
        String[] result_insect = intersect(arr1, arr2);  
        System.out.println("求交集的结果如下：");  
        for (String str : result_insect) {  
            System.out.println(str);  
        }  
  
         System.out.println("---------------------疯狂的分割线------------------------");  
          //测试minus  
        String[] result_minus = minus(arr1, arr2);  
        System.out.println("求差集的结果如下：");  
        for (String str : result_minus) {  
            System.out.println(str);  
        }  
    }  
  
    //求两个字符串数组的并集，利用set的元素唯一性  
    public static String[] union(String[] arr1, String[] arr2) {  
        Set<String> set = new HashSet<String>();  
        for (String str : arr1) {  
            set.add(str);  
        }  
        for (String str : arr2) {  
            set.add(str);  
        }  
        String[] result = {};  
        return set.toArray(result);  
    }  
  
    //求两个数组的交集  
    public static String[] intersect(String[] arr1, String[] arr2) {  
        Map<String, Boolean> map = new HashMap<String, Boolean>();  
        LinkedList<String> list = new LinkedList<String>();  
        for (String str : arr1) {  
            if (!map.containsKey(str)) {  
                map.put(str, Boolean.FALSE);  
            }  
        }  
        for (String str : arr2) {  
            if (map.containsKey(str)) {  
                map.put(str, Boolean.TRUE);  
            }  
        }  
  
        for (Entry<String, Boolean> e : map.entrySet()) {  
            if (e.getValue().equals(Boolean.TRUE)) {  
                list.add(e.getKey());  
            }  
        }  
  
        String[] result = {};  
        return list.toArray(result);  
    }  
  
    //求两个数组的差集  
    public static String[] minus(String[] arr1, String[] arr2) {  
        LinkedList<String> list = new LinkedList<String>();  
        LinkedList<String> history = new LinkedList<String>();  
        String[] longerArr = arr1;  
        String[] shorterArr = arr2;  
        //找出较长的数组来减较短的数组  
        if (arr1.length > arr2.length) {  
            longerArr = arr2;  
            shorterArr = arr1;  
        }  
        for (String str : longerArr) {  
            if (!list.contains(str)) {  
                list.add(str);  
            }  
        }  
        for (String str : shorterArr) {  
            if (list.contains(str)) {  
                history.add(str);  
                list.remove(str);  
            } else {  
                if (!history.contains(str)) {  
                    list.add(str);  
                }  
            }  
        }  
  
        String[] result = {};  
        return list.toArray(result);  
    }  
}  
